The present invention relates generally to the field of electric submersible pump assemblies, and more particularly, but not by way of limitation, to an electric submersible pump assembly having an encapsulated submersible motor and pump.
In oil wells and the like from which the production of fluids is desired, a variety of fluid lifting systems have been used to pump the fluids to the surface. It is common to employ various types of downhole pumping systems to pump the subterranean formation fluids to surface collection equipment for transport to processing locations.
One such prior art pumping system is a submersible pumping assembly which is supported in the wellbore, the submersible pumping assembly having a pump and a motor to drive the pump to pressurize and pass the fluid through production tubing to a surface location. A typical electric submersible pump assembly includes a submersible pump and an electric motor that are directly in contact with the wellbore fluids. Submersible pumping assemblies are often placed in the wellbore months or years before use, causing extended exposure to scale and corrosion. Additionally, motor lubricant can suffer breakdowns such as the loss of motor oil light ends during this period of inactivity. Long periods of inactivity have become more communon, particularly in deep water drill locations where it is expensive to rework a well. The cost of reworking an offshore well to add a submersible pump can be so expensive as to make the remaining reserves uneconomical to produce. Thus, there is a need for a method of effectively protecting the submersible pumping assemblies that are currently being placed in the wellbore and keeping the submersible pumping assemblies free from contamination.
An electric submersible pumping assembly includes, a first sealing device, a first opening device and an encapsulated pumping device. The encapsulated pumping device is disposed between the first sealing device and the first opening device. The encapsulated pumping device includes a pump assembly, a motor assembly and a device body. The motor assembly includes a seal section operably connected to the pump assembly. The device body forms a chamber around the pump assembly and the motor assembly. The encapsulated pumping device transmits production fluids when the first sealing device and the first opening device are open.